Electric lamp



April 25, 1933. H A DOUGLAS 1,905,818

ELEGTRIC lLAMP Original- Filed Feb. 27, 1951 fra/en r Patented Apr. 25, 1933 UNITE stares HARRY A. DOUGLAS, orBRoNso'N, MICHIGAN* ELECTRIC LAMP Original application led February 27, 1931, Serial No. 518,665. Divided and this application filed December 14, 1931. Serial No. 580,889.

My invention relates to electric lamps and is of particular service in connection; with dash lamps Vfor automobiles in which the lamps include an incandescent light bulb.

" Among other objects, my invent-ion aims-to provide an improved dash lampwhichis simple in construction and efficient in operation.

This application is a division of my copending application, Serial No. 518,665, iled February 27, 1931, entitled Circuit continuing devices.

The present invention may be understood from the illustrative embodiment thereof shown in the accompanying drawing, in

which Figure 1 is an axial section, showing some of the part-s in elevation, of a. circuit continuing device embodying my invention;

Figure 2 is a view similar to Figure 1 but rotated ninety degrees and showing some of the parts in elevation; 1

Figure 3 is a sectional view taken kon the line 3 3 of Figure l;

' 25 Figure 4 is a sectional view taken on the line 1 -ll of Figure 1;

Figure 5 is a view taken on the line 5 5 of Figure 1 and showing parts in side elevation and another part in section; and

y Figure 6 is a rear end view taken o-n the line 6 6 of Figure 1.

Referring to the figures of the drawing, I have shown a circuit continuing vdevice such as a dash lamp which may include a cylindrical metallic shell 1, having the integral lugs 2 and 3 adapted to engage and rigidly clamp the shell to a suitable support upon the dashboard such as a bracket, a portion of which is indicated at 4.

The shell l houses a metallic core 5 which is adapted to have rotative and longitudinal movement with respect to the shell as presently described. The core 5 is shown provided with a skirt portion 6 and an axially recessed portion 7, which is apertured at its inner end concentrically 'with the core. The skirt portion 6 is in close proximity to the surface of the bore of the shell. The core 5 is provided withY a tubular portion 8 which is coaxial with the core and is rigidly connected tothe core at the inner end of the recessed portion 7, for example by being *crimped about the margin of the aperture in the re cessY of the core as at 9. The tubular portion 8 loosely mountsa thin metallic washer 10 which is adapted to support the tubular portion 8 in the shell but to permit rotative and longitudinal movement of the tube with -respect to the shell and washer. The washer 10 is maintained in position in the shell 1 by the pressure of a coiled spring 1,1,- which. presses the washer 10 against an abutment such as the ears 12 formed with the shell land bent to lap thewasher 10. The coil spring 11, which bears also against theA conical back of the axially recessed portion 7 of' the core 5, simultaneously presses the core 5 ,and4 its tubular portion 8 longitudinallyofr the shell 1 forwardly and in a direction tending to sep,- arate the corel 5 and the washer 10, movement l, in this `direction being limitedby a flange 13 at the oppositel or rear end of the tubular portion 8. o

The metallic washer 10` is also desirably provided with the peripheral spring fingers 751 40 which permit the washer to Yaccommodate itself to the expansion and contraction of the shell 1 as already described. y Y A current. carrying member is provided in the shell l, which member is hereV repreg()v sented by an insulated wire 14, which is passed looselyv through the Vtubular portion 8 and as here shown has its terminus soldered in a cup-shaped metallic contact member 15, which is concentrically carried by an insulat- 35 ing washer 16, which, in turn isconcentrically carried by the core 5. The Contact member 15 is thus substantially coaxial withthe shell 1. The washer 16 is revolubly held in the axially recessed portionv 7 of the `core 5, as by means of fingers 17 struck from the core and turned tohook loosely over the edge of the insulating washer 16. rllhe insulation of the wire'li is continuous substantially up to the washer 16. So constructed andarranged. the wire 14,-togetherwith the contact `15 and thewasher 16, are free to rotate relatively to the core` 5 and tubular portion 8, and the core 5, in turn, is free to rotate relatively to the shell 1.

A contact carrying plug represented by an incandescent light bulb 18 having a base 19 has bayonet projection and bayonet channel connection with the shell 1, a snug fit of the base 18 with the shell being assured by a spring tongue 20 which is struck from the body of the shell 1 and extends into the bore of the shell. The bayonet pins 21 are thus frictionally maintained in their seats 22. The base 19 is provided witha contact 23 which is coaxial therewith and which in one lof the alternative longitudinal positions of the core 5, engages ,the contact 15 to close the circuit.

Such a position of the complementary con-V tacts 15 and 23 is indicated in Figures 1 andV 2,` in which position the core 5 is being urged forwardlyby the-springll and the contact 23 is beingpressed into the cup-shaped contact 15. Such engagement of the contacts is assured since the core 5 has not reached the limit of its forward movement as determined by the flange 13 on the tubular portion. The cup-shaped contact 15 provides a seat for the contact 23 which'desirably tends to grip the Contact 2 3 and prevent flickering of the light due to vibration of the parts. To enhance this grippingeffect, the periphery of the cupshaped contact member 15 is desirably roughened slightly as at 24 to increase the friction between it and the softer contact 23.

When it is desired to o-pen'the circuit, the core 5 may be moved longitudinally in the shell 1 away fromthe base 19,- thus separating the contacts15'and 23. I have provided means for eifecting longitudinal movement of the core 5 which means is here shown as inclusive of a handle 25. This handle may be locked to the core as by having a'reduced portion 26 of the handle passed through a slot 27 in the skirt 6 of the core. The slot 27 desirably terminates in a wide mouth 28 so that the handle can be removedby appro# priate manipulation of the parts. The handle 25 extends outwardly from the core 5 through a cam slot here shown as the oblique slot 29 in t-he shell 1. By moving the handle in this slot the core may bey rotated, and simultaneously with said rotation, either retracted or advanced in the shell to open or close'the circuit as desired. A seat 30 for the handle 25 in the slot 29 permits the core to be held in a retracted position and the circuit maintained open. rIhe handle 25, having no grooved connection with the margins of the slot 29, has no tendency to stick in the slot but moves freely therein. It is highly desirable that the wire 14 be not rotated by the rotation of the core 5, and by a construction such as I have herein exemplified, the wire 14 with its terminal contact 15 is free to turn relatively to the core when the latter is being rotated during the opening or closing of the circuit, the wire turning freely in the tubular portion 8 and the contact member 15 turning freely in the recessed portion of the core. The wire 14 as here shown is provided with a metallic armor 31 and the armor is desirably continued well into the tubular portion 8 so that friction is prevented between the tube and the insulation of the wire which would tend to fray the insulation. The circuit continuing device here shown for illustration being in the form of a dash lamp, I have shown a cowl 32 over the bulb 18 which directs'the light from the bulb 18, by reason of an opening 33 in the cowl, upon an instrument board of an automoile, for example. The cowl 32 is hereshown cylindrical and is arranged to slip snugly over the shell 1 and is held upon the shell by spring action of the shell. In this instance, the shell l has its wall split longitudinally as at 34 continuing the bayonet channel 34a and leaving a free segmental portion 35 of the shell which acts as a spring to provide a snug lit between the shell and cowl. The portion of the shell upon which the cowl seats includes a tlange 36 which is bent back upon the exterior of the shell and provides an annular bearing 37 for'the cowl. The bearing 37 is desirably spaced from the body of the shell. In accordance with my invention the flange 36 is continued longitudinally rearwardly of the shell as by the spring fingers 38 which, as clearly shown inthe drawing, are decreasingly tapered in longitudinal section and in width toward their free ends to progressively decrease their resiliency. In other words, the material of the ange 36 where it forms the bearing 37 is substantially the same thickness as the material of the body of the shell l, but ,the material of the fingers 38 is progressively thinner from the point where the lingers join the bearing 37 to their free ends. Thus as the cylindrical cowl is forced over the bearing 37 and the ngers 38 the flange and fingers yieldingly engage the cowl and the liange provides a split ring bearing for the cowl of substantially greater resiliency than the fingers 38. The spring fingers 38 being reduced in thickness as well as in width toward their free ends oier substantially less resistance to distortion than the bearing 37 and the fingers at their free ends have substantially no greater resiliency than is necessary to maintain them in frictional engagement with the cowl. So constructed and arranged the function of the spring lingers is merely to frictionally engage the cowl to prevent jarring of the cowl off the'bearing and the spring fingers have substantially no tendency to force the cowl longitudinally of the shell and thus oft1 of the shell as they would have if they were of uniform thickness with the material of the iiange 36 forming the bearing'r37. An internal ribc39 on the cowl desirably limits the extent of its engagement with the flange 36. Y It will beunderstood that the circuit here shown for purposes of illustration is a s0- called single pole circuit in which the bulb 18 may be grounded through a metallic sheath surrounding the base 19 and the metal of the parts.

Obviously, the invention is not limited to the particular details of construction here shown. Furthermore, it is not indispensable that all features of the invention be employed conjointly, as they may be advantageously used in various combinations and sub-combinations.

I claim:

l. A dash lamp or the like embodying, in

combination, a cylindrical metallic shell of resilient material split longitudinally; a flange at the forward end of said shell, said ange being turned back over the body of the shell and extending longitudinally rearwardly thereof spaced from said shell; continuations of said flange extending longitudinally rearwardly in the form of spring fingers, the material of said fingers being decreasingly tapered in longitudinal section toward their free ends to progressively decrease their resiliency; and a cylindrical cowl, Said cowl telescoping over said flange and said lingers which yieldingly engage the cowl, whereby Said flange provides a split ring bearing for the cowl and said fingers at their free ends have substantially no greater resiliency than is necessary to maintain them in frictional engagement with the cowl. Y 2. A dash lamp or the like embodying, in combination, a cylindrical metallic shell of resilient material; a. split flange at the forward end of said shell, said flange being turned back over the body of the shell and extending longitudinally rearwardly thereof spaced from said shell; continuations of said flange extending longitudinally rearwardly in the form of spring fingers, the material of said lingers being decreasingly tapered in longitudinal section toward their free ends to progressively decrease their resiliency; and a cylindrical cowl, said cowl telescoping over said flange and said fingers which yieldingly engage the cowl, whereby said flange provides a split ring bearing for the cowl and said ngers at their free ends have substantially no greater resiliency than is necessary to maintain them in frictional engagement with the cowl.

In witness whereof, I hereunto suscribe my name.

HARRY A. DOUGLAS. 

